The present invention is concerned with an alkaline product, in particular, but not exclusively, potassium hydroxide, destined to be used in odontiatria for the chemical removal of dentinal pulp in the devitalization operation, commonly called "root canal cure" by those skilled in the art.
During past years, dental surgeons changed their operating philosophy from an eminently demolishing one into one preservative and curative of dental structures. This is because of the greater attention paid to the biomechanical characteristics of mastication which caused people to ackowledge that the chewing load is too high to be supported without damage by the bone structures of gums only. Implantology has often solved the problem of the lack of dental structure but, although it represents a considerable progress, implantology cannot do better then physiologic structures, even if mutilated, and "dead" from a biological viewpoint. So, even a tooth stump, or an isolated root, became invaluable as anchoring points for prostheses which should reproduce the "normal" anatomicofunctional situation as closely as possible.
The most important among the problems deriving from the choice of the preservative treatments is the problem of the removal, which should be as complete as possible, of the tissues left by the inflammatory/flogistic state which led the patient to the dental surgeon. In fact, only in that way the structure of the concerned tooth--or of tooth residues--can be safeguarded over time. The whole preservative treatment rests hence on a perfectly carried out tooth canal cure. Therefore, the essential importance is self-explanatory, namely the prevention of the repetition of pathologic events due to infected residue which were not properly removed in due time.
The mechanical means adopted heretofore for the root canal cure are by now "classic" components of odontiatric instruments: drill, cutters, stylets, nerve extractors. All of these instruments share the need of a considerable tecnical capability, supported by an uncommon "natural" skill of the operator. Therefore, it is not surprising that the number of odontologists who are capable of carrying out a conservative canal cure with good probabilities of success is rather small. The same variability of root canal reduces the possibilities of a really effective treatment. It is enough to think of the impossibility of reaching undercuts or side branchings of a root by means of a straight instrument, in order to realize the difficulties which have to be overcome through instrument techniques.
In short, what the prior art proposes, is performing root canal cures by means of such mechanical means as drills, cutters, and the like, in order to remove root pulp tissues without that the latter having been submitted to any preliminary chemical treatments.
The use of these instruments also implies a painful mechanical action on the concerned part, in order to open and ream the root canal in order to be able to devitalize the tooth by means of the removal--still by means of mechanical instruments--of the nerve.
The so devitalized tooth must be submitted then to a series of treatments, during the course of a certain number of sittings, spaced in time, which should only be carried out by very qualified and skilled people in order to prevent possible residues of pulp tissues, not duly removed, from giving rise to centres of infection or necrosis with abscesses or granulomas consequently occurring.
Therefore, such an operating system is very expensive and a perfect outcome thereof is always subordinated to the capability, skill and professionalism of the operators.
In the search for an alternative method, those skilled in the art had already thought of the possibility that a liquid, fed to the interior of the pulp shell, may reach the otherwise inaccessible points. In fact, solutions of various substances have been long used in odontiatria for the purpose of obtaining a reasonable hope of a successful outcome of even mechanically difficult root canal cures.
For example, such solutions are the solution of sodium hydroxide or sodium carbonate, at concentrations of about 5-10%, used seldom, for fear that it is excessively caustic; organic mixtures which perform a solvent/dehydrating action (e.g., acetone+ether+isopropyl alcohol), also used in order to dry the root canal; solution at 3% or 5% Chloramine T; solution at 17% of EDTA as trisodium salt (generated in solution from diNa EDTA+sodium hydroxide); sodium hypochlorite solution at 5.25%; and hydrogen peroxide solution at a concentration of from 3 to 5% by weight. All of these solutions have been boasted of being capable of dissolving tooth pulp. Actually, what is secured is the mummification of tissues, and their chemical sterilization, while the removal action is still entrusted to the manual skill of the operator. Tests carried out in vitro on a tissue obtained from butchery wastes have confirmed the above statements. In fact, the above cited solutions, and their mixtures, were tested, with uncertain results, and in no case was the assured pulp demolition achieved. Further experiences in vitro, also submitted to statistic analysis in order to verify the reliability and the possible correlation of the results, have confirmed that which had already been intuitively concluded on the basis of the preceding test series. In particular, the solution of Chloramine T (sodium p-toluene-sulfonchloramide) and the solution of EDTA at 17%--which is capable of softening dentine by substracting calcium ions from it, but shows to be ineffective versus pulp tissues--showed to be very disappointing, as regards their specific use in odontiatria.
Further studies carried out on pulp nature which evidence the poor effectiveness of alkaline (sodium hydroxide and sodium carbonate) solutions caused researchers to focus their attention on the nature of the fatty acids contained in pulp, which generally are long-chain acids (chain length longer than C.sub.16). The explanation of the poor effectiveness had hence to be seen in the relatively low saponifying power of sodium alkalies and in the poor solubility of the soaps formed in the reaction, besides a considerable resistance of the proteinic matrix to undergo degradation, but under drastic conditions, decidedly unproposable in an intervention on a patient (high temperatures, times of the order of several hours).